Lifting jack



April 22, 1941- M. B. I UcKER 2,239,268

' n LIFTING JACK l 5 Sheets-Sheet 1 Filed Dec. 14l 1959 36 INVENTOR April 22, 1941 M. B. LUCKER LIFTING JACK Filed Dec. 14, 1959 5 Sheets-Sheet 3 leas.: A.

ATTORNEYJ,

lifting jack f the a friction clamp or cam type Patented Apr. 22, 1941 UNITED STATE 2,239,268 LIFTINQ JACK Millard B.

Lucker, St. Joseph, Mich., assignor to Auto Specialties Manufacturing Company, St. Joseph, Mich.,` a. corporation of Michigan Application December 14, 1939,

16 Claims.

This invention relates to lifting jacks, and particularly to jacks of the friction gripping clamp or c am type. y

It is an object of the invention to provide a friction clamp or cam type which is of improved construction and operating characteristics.

More particularly, it is an object of the inven- `tion to provide a friction clamp or cam lifting jack wherein the jack load-lifting member may be operated in predetermined step increments of movement both during load-raising and loadlowering operations.

A further object of the invention is to provide lifting jack wherein the load-lifting member may be raised or lowered in predetermined step 'increments of movement and wherein the yload-lifting member and the load supported thereby are at all times under positive and accurate control insuring uniformity and safety in the operation of the jack device. In accordance with the invention the jack construction is provided with actuating and holding friction clamps or cams, and means isprovided for automatically shifting the weight of the load from one to the other of the clamps during load-raising and lowering operations, at least one clamp being at all times operative to support and maintain control of the load movements.

A still further object of the invention is to provide a friction clamp or cam type lifting jack wherein the load may be raised or lowered in predetermined step increments of movement by the manipulation of a single operating lever, conditioning or control means being provided for deseriarNo. 309,139

termining the direction in which the load-lifting member will be moved as the lever is actuated.

Various other objectsadvantages and features of the invention will appear from the following specification when taken inv connectionvwith the accompanying drawings, wherein a preferred embodiment of the invention is set forth for purposes of illustration.

In the drawings, wherein like reference 'numerals refer to like parts throughout:

Fig. 1 is a general sideassembly view of a liftingv jackconstructed in accordance with one preferred form of the invention.

Fig. 2 is a front sectional view of the jack structure shown in Fig. 1, on the line 2-2 thereof, particularly illustrating the internal construction of the lifting body and its associated parts. The structure is illustrated as loadraising operations.

Fig. 3` is a view generally similar to Fig. 2,

l to be raised, which conditioned for 'd lat its upper end with a projection but showing the structure as conditioned for load-lowering operations.

Figs. 4 and 5 are transverse sectional views of the structure of Fig. 1, taken on the lines 4--4 and 5-5 respectively thereof.

Fig. 6 is a detail perspectiveview of the main lifting body.

Fig. 'I is `a detail perspective of the auxiliary frame adapted to be associated with the main frame'or lifting body.

Fig. 8 is a detail perspective of the operating lever. f y

Fig. 9 is a side sectional view ofthe structure of Fig. 1, more particularly illustrating the internal operating mechanism, and Figs. 10 to 14 inclusive are views generallysimilar to Fig. v9 but showing various operating p0- sitionsv of the mechanism. Figs. 9 and 10 show the structure during load-raising operations, and Figs. 1l, 12 13 and 14 show the structure during load-lowering operations.

Referring more particularly to the drawings, the structure illustratedcomprises an circularshaft I0, partially broken away, as 1llustrated in Fig. 1, carried in any suitable manneron a` base II whichisv adapted to rest upon the ground or other supporting surface. A main lifting body or frame I2 is mounted for longitudinal sliding movement along the shaft I0 to effect load-raising or lowering movements, the raising or loweringpf the lifting body being under the control of friction clamp or cam operating mechanism, presently to be described.

The main lifting body I2 may conveniently be formed as a one-piece casting provided with a central bore through which the shaft IIlis adapted to project. The upper end ofthe lifting body is provided with a cylindrical or sleeve portion I3 adapted to support a rotatable load-engaging collar I4. The load-engaging collar is provided with a laterally projecting seat portion I5 adapted tobe Vbrought into engagement with the load may, for example, be the bumper of an automotive vehicle as illustrated by the reference numeral I6. While the lifting jack illustrated is thus of the automobile bumper jack type, it is to be understoodthat the principles of `the ir vention may be adapted to lifting jacks and related structures of other types and kinds, and adapted for other purposes. The lower edge of the load-'engaging collar is arranged to seat upon an annular bead I1 formed on the lifting body, and the cylindrical sleeve portion I3 is formed I8 adapted to 'prevent the inadvertent dislodgment of the loadupstanding engaging collar in the event that the jack struc- I3 constantly urges the actuating clamp 39 upture is inverted, as when not in use. wardly into engagement with the barrier wall Il, As shown, for example in Fig. 9, the lower end l as illustrated in Fig. 9. The spring Il, during of the bore of the lifting body sleeve I3 is procertainphaseaoftheoperation, engages the holdvided with a portion I9 of reduced diameter. The 5 ing clamp, whereas in other phases of the operabore section I9 is adapted to cooperate with tion the spring is out of contact with the clamp, struck-out projections 2l formed on the upper as will be later described. end of the shaft III to prevent the projection of Anoperating lever Il lspivotally mounted upon the lifting body upwardly ci! of the end of the the lifting body, on a pivot pin Il, the pivot pin shaft. 'I'he projections however may be received 10 being carried by a pair of projecting ears 5l and within the bore portion 2| oi' the sleeve as the Il. Pig. 4, formed on the lifting body. As best lifting body is raised, whereby to increase the shown in Pig. 8, the operating lever is of tubular effective height of the jack. construction and adapted to receive an extension The lifting body I2 is provided with a chamber bar Il, 'preferably removable. The bar Il may 25 adapted to receive an auxiliary frame 29 and ll5 be of any suitable length to provide the necesthe associated jack operating mechanism. The sary leverage in the operation of the lever. The auxiliary frame is also provided with a central operating lever is provided with a cross-shaft Il bore through which the shaft I9 projects and is which is adapted to engage the upper face of the somewhat less in length than the vertical height extension portiong 6| of the actuating clamp of the chamber 25 whereby to permit the auxil- 20 plates. Theoperating lever isalso provided with 25 and theupper wall 28 of the auxiliary frame 25 ture. and the control lever 2l adjusted to the lever is provided with an operating portion II 30 the downward thrust of Spring 21 subdiiioned for lood-lowering operations. #minst the actionof com spring 21. as The auxiliary frame is provided with a cen- 4 in Pisa 2 and 9; @using the sprintr Il to trally disposed barrier wall 35 forming within the frame an upper chamber 36 `and a lower 0f the holding Clamp Il. 'Ihis cinises the clamp chamber 31, The upper chamber is adapted to to be urged or canted coimterclockwise, as seen in 9, into holding or shaft-gripping position.

being cut away to bring the biting clamp edges 50 reference to horizontal or inclined position. In

ably composed of a plurality oi' laminated plates, retrograde movement 13 DreVented- Attempted as Shown, e movement causes the shoulder 45 of The holding clamp 39 is provided with a radial- 55 the 111191118 body 1if) engage the projection 42 0f ly extending projection I2 adapted to be received the holding olemp further tending to cent the within an opening as formed in the lifting body Clamp 01' use it t0 811D the Shaft The wmand an opening Il formed in the auxiliary frame. m9551011 spring 53 normally seats the meting 'I'he upper and lower shoulders or edges I5 and clamp assembly 3 asn-11131; the neme Wen 35 1n 4s of the lifting body opening are adapted to en- 60 imperative 0r uncanted position, as seen in Fis. gage the clamp projection, thus controlling the 9- Aoool'dmgly 71th the parte oond1t1ned es operation or the clamp hereinafter to be de- ShOWn 111 P188- 2 wd 9. the lifting body may be scribed. The auxiliary frame opening u is of manuell? fol'd upwardly *10118 the Shaft "into greater vertical extent than the opening Il. It engagement wml the 10nd' neither the holding merely provides clearance i'or the clamp pro- 65 olemD nor the tuning C18-mp' interfering with jection and its edges do not operatively -engage $1118 movement 0f the 1131118 body. therewith. l The lifting body may then be further moved A coil springv 59 is arranged between the barupwardly along the shaft to raise the load by rier wall 35 and the holding clamp, encircling the manipulation of the Operating lever 55. The acshaft Il. 'Ihe ends of thespring 59 are anchored 70 tion of the operating mechanism during lifting into the barrier wall as best shown at 5I and 52 operations will best be understood by reference to in Fig. 5. A compression spring 53 encircles the Figs. 9 and 10. As the operating lever is pulled shaft I Il within the chamber 31 and bears beupwardly, or pivoted oounterclockwise, as seen in tween the actuating clamp assembly and the r Figs. 9 and l0, the cines-shaft Il engages the iower wsii az or the auxiiiary imno. 'niespring 7 actuating clamp contini; it clockwise info gripnormal Fig. 9 position. The compression ling the auxiliary frame 2l from l. further downping engagement with the shaft I0. against the action of the spring 53. The actuating clamp thereupon acts as a reaction ybase for the shaft 60, so that upon further movement of the operating lever 55 the lifting body l2 will be raised by means of the pivotal connection 55 between the lifting body and the operating lever. During this upward movement of the lifting body, the control member 29 causes the auxiliary frame 26 to move upwardly as a unit therewith. Accordingly the spring 50 is maintained in continuous engagement with the holding clamp 38 maintaining it in canted or locking position. The holding clamp in such position may move upwardly along the shaft I0, but retrograde or downward movement of the clamp or lifting body with respect to the shaft is prevented. The position of the parts at the end of the upper stroke of the operating lever is shown in Fig.` 10. As the operating lever is now moved downwardly or restored to normal position, the holding clamp prevents downward movement of the lifting body, and the actuating clamp is moved upwardly along the shaft I and restored to its spring 53 restores the actuating clamp, and in the event that the clamp should tend to stick, the projections 62 and 63 on the operating lever will engage and Ipositively release the clamp. This operation may be repeated to raise the load step by step the desired amount.

The load-lowering operations will be best understood with reference to Figs. 11, 12, 13 and 14. To effect lowering movements, the control lever 25 is first released to its Fig. 3 position, permitting the compression spring 21 to force the auxlliary frame 2B downwardly, causing the lower wall 32 of the frame to seat against the lower wall of the lifting body chamber 25. This causes from the holding the holding clamp the weight of the load on the clamp, by reason of the contact between the lifting body shoulder 45 and the clamp projection 42, maintains the clamp in canted or holding position.4 The operating lever 55, hich is now in its Fig. 11 position, is then moved upwardly or counterclockwise to again bring the shaft 60 into engagement with the actuating clamp 39. The engagement between the operating lever and the actuating clamp causes the clamp to be canted into gripping engagement with the shaft, serving as a reaction base and resulting in the slight raising of the lifting body as the operating lever is raised. As the lifting body shoulder 45 is lifted away yfrom the holding clamp, the clamp falls by gravity into its uncanted or release position, Fig. 12; or alternatively in the event the holding clamp should tend to stick in holding position, the lower lifting body shoulder 46 will engage the clamp projection 42, as illustrated in Fig. 12, positively moving the clamp to its release position. While the holding clamp is now released, it is to be noted that the actuating clamp is in active or gripp'ng position, thus serving as a support means for the lifting body and the load through the intermediary of the operating lever andthe pivot connection B.

As the operating lever is now moved downwardly, or clockwise, the lifting body will be lowered. 'As the movement progresses the actushaft I0,

as indicated at the point 65 in Fig. 13, thus hold- 75 ward movement. Inasmuch as the auxiliary frame is held from further downward movement whereas the lifting body I2 will continue to move downwardly with the operating leve separation between the lifting body and auxiliary frame takes place as shown in Fig. 13, overcoming the action of the compression spring 21. The holding clamp 38 moves downwardly with the lifting body, whereas the spring 50 is held stationary with the auxiliary frame. AAccordingly as the movement progresses the springv engages the clamp and intimately againcants itinto locking This position `-of' thelparts is .shown position.

in Fig. 13, just priorto'the time of. engagement between the holding clamp projection 42- andthe v to be lnoted that actuating clamp and lifting body shoulder 45. It is the contact 65 between the the barrier wall of the. auxiliary framev tends to move the actuating canted position. Howevenhthe force of the spring 21 which determines the force of contact at this point is insullicientto overcome the force of the load which maintains the clamp in canted position. In other words, during the lowering motion of the lifting body just described, the entire weight of the load is carried by the actuating clamp at its point of contact with the shaft 60 of the operating lever, and this contact insures the maintenance of the actuating clamp in shaftgripping position.

When the lowering movement progresses to the point indicated in Fig. 14, wherein the shoulder 45 of the lifting body engages the holding clamp,

the lifting body becomes supported by the hold-v ing clamp. As this engagement occurs further downward or clockwise movement of the operating lever causes a release of the pressure engagement between the shaft and the actuating clamp. Immediately as this takes place the actuating clamp is released from the shaft, and the compression spring 217thrusts the auxiliary frame downwardly, the partsr assuming the position illustrated in Fig. 14. The actuating clamp is released, but the holding clamp isnow in canted or load-supporting position, and due to the fact that it is the assumption of the load by the holding clamp which causes the release of the actuating clamp it is insured that at least one of the clamps will always be in control of the load. To effect further lowering of the load, the operating lever is again raised as illustrated in Fig. l2 to cant the actuating clamp into gripping engagement with vthe shaftrand the cycle of operation is repeated.

The structure provides a lifting jack of the friction gripping clamp or cam type wherein both the load-raising and load-lowering operations may be effected from a single operated lever in step by step fashion or in predetermined increments of movement. The mechanism is conditioned for load-raising or load-lowering merely by the proper positioning of the control lever 29. The movements of the lifting body both upwardly and downwardly are controlled at all times, at least one of the gripping clamps being continuously operable to support and control the load. Uniformity and, safety of operation is assured.

clamp into released orn unbut only as indicated in the with respect to the base and for causing the spring to alternately engage and disengage the holding clamp as the load-engaging member is moved in the opposite direction with respect to the base.

2. A lifting standing shaft jack comprising agbase, an upmounted o n the base, a lifting a load-engaging member longisaid clamps being an actuating clamp and the clamps being a holding clamp, an operating member for controlling the movements of the clamps, a spring engageable with the holding clamp, and means for maintaining the spring in constant engagement with the holding clamp during movement of the lifting body in one direction along the shaft, and for causing the spring to alternately engage and disengage the holding clamp` during movement of the lifting body in the opposite direction along the shaft. v

3. A lifting jack comprising a base, a loadengaging member, means for moving the loadengaging member relative to the base comprising a housing and a pair of friction clamps associated therewith, one of said clamps being an actuating clamp and the other of the clamps being a holding clamp, an operating lever pivoted to the housing for controlling the movements of the clamps, a frame carried by the housing, a control lever for shifting the frame relative to the housing, and a spring controlled by the position of the frame and engageable with the holding clamp, the spring being in constant engagement with the clamp when the frame is in one position of adjustment as the load-engaging member is moved in one direction with respect to the base, and the spring being alternately engageable and disengageable with the holding clamp when the frame is in another position of adjustment as the load-engaging member is moved in the opposite direction with respect to the base.

ck comprising a base,- a loadengaging member, means for moving the loadengaging member relative to the base comprising a housing and a pair of friction clamps associated therewith, one of said clamps being an actuating clamp and the other of the clamps being a holding clamp, an operating lever pivoted to the housing for controlling the movements of the clamps, a control lever pivoted to the housing, a frame shiftably mounted within the housing, a spring for urging the frame into one position with respect to the housing, said control lever being operable to shift the frame to another position of adjustment within the housing, and a spring engageable with the holding clamp, said last named spring being constantly engageable with the clamp when the frame is in one position of of said clampsv being other of the` adjustment as the load-engagmember in one direction 'engaging member relative to ing member is moved spect to 5. A lifting jack'comprising al base, engaging member, means for moving the loadengaging member relative to the base comprising sition,

ing a pair of friction clamps,

engaged.

8i-A lifting jack comprising a baseya. loadengaging member, means for moving the loadengaging member relative to the base comprising a pair of friction clamps,

engaging engaging member relative to ing a housing and a moving the loadthe base compris- 10. A lifting jack comprising a base, a'loadengaging member, means for moving the load u the actuating clamp v baille wall ating clamp and clamps to move thereof, and means for controlling y aasaacs engaging member relative tothe base comprising a housing and a pair of friction clamps associated therewith, one of. said clamps being an actuating clamp and the other of the clamps being a holding clamp, an operating lever pivoted to the housing and engageable with the actuating clamp, abaiile wall operatively associated with the housing, a spring for normally urging into inoperative position against said wall, a fulcrum formed on the housengage, a spring supported by said baille wall for urging the holding clampinto operative position against sai fulcrum, and means for shifting the thin the housingl for moving the last which the holding clamp isadapted to clamps to*v housing for operating the clamps, said operating lever having operating connection with the move the load-engaging member in step by step increments of movement both upwardly and downwardly with respect to the base upon lever operation, and control mechanism operatively associated with the clamps for connamed spring into engagement with the holding clamp. v

l1. A lifting Jack comprising a base, an upstanding shaft mounted on the base, a lifting body including a load-engaging member longitudinally movablevon the shaft, means for moving the lifting body along a pair of friction clamps, one of said clamps being an actuating clamp and the other, of the clamps being a holding clamp, an operating lever pivoted to the lifting body engageable with the actuating clamp, sociated with the lifting body, afspring for urging'the actuating clamp into inoperative posi,- tion against said wall, a fulcrum formed on the lifting body against which the holding clamp is adapted to be operatively engaged, a spring supported by said baffle Wall engageable with the holding clamp for urging it into operative posiltion against said fulcrum. and means for shifting the baille wall within the lifting body for moving said last named spring into operative engagement .with the holding clamp.

12. A lifting jack comprising a base, a loadengaging member, and means for moving the load-engaging member relative to the base come a housing, a pair of friction clamps associated with the housing and mounted on the shaft, one of said clamps being an actuthe other `of the clamps being prising a shaft,

a holding clamp, the housing for operating the clamps, said operi` ating lever having operating connection with the the loadengagingmember in step bystep increments of \movement`both upwardly and kdownwardly with respect to the base upon lever operation. and control mechanism operatively associated with the clamps for cona baille wall operatively asan operating lever plvted toN the shaft comprising a holding clamp, the housing for operating the clamps, said opertrolling the manner of movement of the clamps upon operation of the lever, said control mechanism comprising a frame shiftably mounted on the housing and operatively connected with the holding clamp `for controlling the operation including a manually adjustable control handle and said operating lever the shifting of the frame.

13. A lifting jack comprising engaging member.' and means for moving the load-engaging member relative :to the base comprising a shaft, a housing. a pair of friction ps associated with the housing and mounted ating a base, a loadthe housing and operatively connected with the holding clamp for controlling the operation thereof, and means including a manually adjustable control handle and a spring for controlling the shifting of the frame.

14. A' lifting jack comprising a base, a loadengaging member, and means for moving the load-engaging member relative to the base comprising a shaft, a housing, clamps associated with the housing and mounted on the shaft, one of said clamps being an actuating clamp and fthe other of the clamps being a holding clamp, an operating lever pivoted to the housing for operating the clamps, said. operating lever having operating 'connection with the clamps to move the load-engaging member in 'step yby step increments of movement both upwardly and downwardly with respect to thebase upon lever operation, and control mechanism operatively associated with theclamps for controlling the manner of movement of the clamps upon operation of the lever, said control mechanism comprising a selectively adjustable manual control handle and a coiled spring encircling the shaft and operatively engageable with the actuating clamp.

v15. A lifting jack comprising a base, 'a loadengaging member, and means for moving the load-engaging member relative to the base comprising a shaft, 4a, housing, a pair of friction clamps associated with the housing and mounted on the shaft, one of said clamps-being an actuating clamp and the other of the clamps being. an operating lever pivoted to ating lever having operating connection with the clamps to move the load-engaging member in step.k by step increments of lmovement both upwardly and downwardlgrwith respect to the base upon lever operation, and control mechanism operatively associated with the clamps for controlling the manner of movement of the clampsv upon operation' of the lever, said control mechanism comprising auselectively adjustable manual control handle. a holding -clamp spring posi? tioned by said control handle and adapted to operatively engage the holding clamp, and an actuating clamp spring encircling the shaft and adapted to engage the actuating clamp for controlling the operation thereof.

16. A lifting jack as defined in claim 15 wherein the holding clamp is disposed on the shaft above the actuating clamp, wherein the holding clamp spring is arranged between the holding clamp and the actuating clamp, and wherein the actuating clamp spring is disposed below the actuating clamp and engageable with the lower surface thereof. I

' MILLARD B. LUCKER.

a pair of friction` 

